Individuals and enterprises communicate via computer networks. Because computer networks are expensive to establish and maintain, individuals and enterprises often form contracts with network service providers (NSPs). In exchange for some consideration, a NSP agrees to provide access to a computer network. After forming such an agreement, the individual or enterprise may use the computer network to communicate. In the context of a NSP agreement, the individual or enterprise may be referred to as a subscriber.
Using a computer network for communication may have one or more disadvantages. For instance, congestion on the network may substantially hinder communication between locations. In addition, malicious users on the network may intercept communications flowing between locations.
To address these disadvantages, a NSP may offer quality of service (QoS) guarantees to subscribers. For example, a NSP may reduce the likelihood of congestion delays by routing communications from the subscriber along a low-congestion path through the network that the NSP has specified in advance. The process of specifying a path for a type network communication is known as traffic engineering. Additionally, to enhance security, the NSP may provide a virtual private network (VPN) to the subscriber. In this case, the NSP may encrypt network communications and route the network communications only through trusted intermediate network devices. NSPs may use various communication protocols on the computer network to provide QoS guarantees and/or VPNs. For example, NSPs may use a label switching protocol, such as the Multi-Protocol Label Switching (MPLS) protocol or the Generalized Multiprotocol Label Switching (GMPLS) protocol, to provide engineered and/or secure label switched paths (LSPs) through the network.